The reaction of isocyanates with amines is known in the art and is an extremely fast reaction. It has only been recently that higher molecular weight diamines could be made to react with diisocyanates in a controlled fashion. Work in this area led to the Reaction Injection Molding (RIM) process for the preparation of polyurea plastics.
Reaction of polyisocyanates with polyamines that were soluble or partially soluble in water has often led to gel formation though it might have been expected there would be advantages to carrying out the reaction in water, in that the water would serve as a heat sink.
In contrast to the isocyanate-amine reaction, the reaction of alcohol-isocyanate proceeds at a slower rate. The isocyanate polymers prepared from polyol and isocyanate are well-known and used widely in commercial processes. (see J.H. Saunders and K.C. Frisch, High Polymer Vol. XVI, polyurethanes: Chemistry and Technology (part 1) Interscience publishers (1962)).
In the references discussed below there is information regarding the preparation and use of polyol-isocyanate prepolymers.
Chung et al. disclose in U.S. Pat. No. 4,590,254 a poly(urethane-urea) which is prepared by reverse addition of an isocyanate-terminated prepolymer to an organic medium containing a chain extender such as hydrazine.
In U.S. Pat. No. 4,617,349, Nasu et al. disclosed a urethane resin composition which comprises a polyisocyanate component having from 20/80 to 80/20 of a weight ratio on a solid basis of an .alpha.,.alpha.,.alpha.',.alpha.'- tetramethyl-xylylene diisocyanate derivative to a hexamethylene diisocyanate derivative and an acrylic polyol.
In U.S. Pat. No. 4,611,043 there is disclosed a coating composition prepared from (a) an isocyanate terminated prepolymer which comprises the reaction product of at least one polyurethane-forming reagent containing a plurality of isocyanate groups and at least one polyfunctional polyhydric alcohol and (b) dicyclopentenyl alcohol.
The above prepolymers were generally prepared from polyols and diisocyanates using a tin catalyst and elevated reaction temperatures.
U.S. Pat. No. 4,609,718, discloses a coating composition consisting essentially of a linear acrylate-terminated polyurethane oligomer, including urea groups, introduced by the presence in the oligomer of a reaction product with an isocyanate functionality of about 30% to about 90% by weight of the acrylate-terminated oligomer of a polyoxyalkylene diamine having a molecular weight in the range of from about 1000 to about 8000.
It would be a novel method and a distinct advance in the art if a plant could use disecondary amines and alkyl diisocyanates to produce two different products, each a novel composition having very desirable properties for use in various related arts.
Alkyl diisocyanates and derivatives of disecondary amines, including N,N'-diisopropyl JEFFAMINE.RTM. amines, can be used to produce novel isocyanate prepolymers or disecondary amines by varying molar ratio, order of addition and, in some cases, solvent.